Genetic Studies on an Awnness Gene An-4 on Chromosome 8 in Rice, Oryza sativa L..

Abstract

An awnness gene which was isolated through breeding of an isogenic line of an awnless cultivar Taichung 65 with interchange chromosomes 4-8, was independently introduced into Taichung 65 (T65) after ten backcrossings. The mode of inheritance for the awn trait was examined on the basis of two measurements, the percentage of awned spikelets per panicle and average awn length of ten spikelets, using breeding materials in the B8F2, B9F1 and B1OF1 generations. Experimental results showed that the trait was controlled by an incomplete dominant gene and that recessive homozygotes produced completely awnless spikelets, while dominant homozygotes produced longawned spikelets in a high percentage of awned spikelets per panicle, while heterozygotes produced short-awned ones in a low percentage.